1. Field of the Invention
This invention generally relates to wireless communication systems. More particularly, the invention relates to a wireless digital CDMA communication system that selectively adjusts the data transmission rate depending upon the bandwidth required by the communication without the loss of data during the transmission rate adjustment.
2. Description of Related Art
The telecommunications industry has recently experienced strong growth in the use of wireless technology including cellular, satellite and microwave communications. As the popularity and use of wireless communication systems has increased, the finite bandwidth allocated to each type of wireless communication has become increasingly valuable. Since it is unlikely that additional bandwidth to support user growth will be allocated for existing applications, many of the recent advances in telecommunication hardware and software have been directed toward increasing the transmission rate of data while utilizing the same or a decreased bandwidth.
One of the problems associated with wireless communication of data is that many different types of communicating nodes are currently in use including computers, facsimile machines, automatic calling and answering equipment and other types of data networks. These nodes may be able to communicate at a plurality of different data rates and must be properly synchronized to avoid losing data during the establishment or maintenance of a communication.
The establishment and synchronization of communications is currently performed using a variety of different techniques. For example, the system disclosed in U.S. Pat. No. 4,384,307 (Kuzmik et al.) includes a communication adapter for interfacing a transceiver to a communication line. The system requires bit level manipulation of data to properly synchronize two communicating nodes. Reformatting of data using this technique is computationally expensive and prone to errors.
Another type of system is disclosed in U.S. Pat. No. 4,583,124 (Tsuji et al.) which permits two nodes to quickly establish synchronization at a desired communication speed by storing information concerning each communicating node in memory. However, requiring an originating node to store information about each receiving node is impractical given today's communication environment.
Accordingly, there is a need for a simple and effective technique for switching the data transmission rate of a communication network to the required rate while preserving the integrity of the data transmitted between two communicating nodes.